Method of slaking lime.



A. ZEMMERMANM.

METHOD OF SLAKING LEME.

APPLICATION FILED AUG. 18. 1916.

i1. 5 Pzmnted Feb. 5, 1918.

5] wve'ntoz $513 anew $13 r AN, OF BROOYN', NEW YORK, ASSTGNOR TO THEESTATE OF LOWEHD METHOD OF SLAKINGLIME.

menses.

$peeification of Letters JPate-nt.

Patented Feb. 5, 191%,

original. application filed February 12, 1915, Serial No. 7,?57. Dividedand this application filed. August 13,

1916. Serial No. name.

To all whom it may concern:

Be it known that l, ALBERT ZIMMERMAN, a citizen .of the United States,residing at the city of New York, in the borough of Brooklyn and Stateof New York, have invented certain new and useful Improvements inMethods of Slaking Lime, of which the following is a full, clear, andexact description.

My invention resides in an improved method of slaking lime.

I have discovered that, in the manufacture of hydrated lime, the bestresults are obtained only when complete'liydration of the unslaked limeis efi'c'ted. In order to accomplish complete hydration, it is necessaryto use an excess of water, but this lowers the temperature of thehydrating zone of ing unsla the apparatus below that which is essentialto properly sustain the chemical reaction which takes place, and whenthe apparatus is thus chilled the resultant product is of inferiorquality. According to my invention, I use an excess of water for slakingor hydrating and supply to the slaking zone of the hydrating apparatus,heat in addition to that produced by the reaction between the lime andwater.

My improved method consists in supplyed lime to an elongated containeror chamber, supplying water to the lime" in the container in quantitiesgreatly in excess of the amount required for slaking, and

applying additional heat to the slaking zone of the container to preventthe temperature thereof from tailing below that required for properslaking.

It also consists in certain features and details, which will behereinafter more fully described and claimed.

Una form of apparatus in which myimroved method may be carried out hasbeen illustrated in the accompanying drawings, in which thefigurethereof is a sectional side elevation.

The apparatus illustrated is a modification of and improvement upon theapparatus disclosed in the patent to Kritzer, No. 932,789, dated August31, 1909. The same consists at an elongated container or chain her inwhich the slaking and subsequent drying operations are carried out, thesaid contamer being rnade up of the horizontal drums 1, 2, 3 and l, thedrums 1 and 2 being connected to each other at one end by a fixed hoodor chute 5, the drums 2 and 3 being connected to each other by a similarhood or chute 6 and the drums 3 and 4 being connected together by thefixed hood or chute 7, so that there is a continuous, closed, zig zagpassage through the apparatus, including each of the drums. Extendingaxially 110 and water is supplied in a finely divided condition throughthe stack 11, which communicates with the drum. The slaking zone of theapparatus is almost wholly within the drum 1, although some of theslaking may be performed after the material passes into the drum 2.Throughout the greater part of the drum 2 and in the drums 3 and 4 andtheir connected end portions, the slaked or hydrated lime is dried, sothat when the same is delivered from the discharge end of the container,that is, from the drum 4, it is in the form of a dry powder. 1

I have found that an improved product may be obtained by adding to theunslaked lime in the slaking zone of the container, that is, in the drum1, quanrequired for slaking. In this way, complete and perfect hydrationof the unslaked lime may be obtained, but as the addition of an excessof water tends to reduce the temperature of the container to a pointbelow that which is essential to. proper slaking, T supplyadditionalheat to the slaking zone by surrounding the drum 1 with a.

steam jacket 12. One or more of the drums 2, 3, 4L, may also be suppliedwith a similar steam jacket. Through these jackets a current of steam ispassed, which not only prevents the temperature of the mass undertreatment in the slaking zone of the appa ratus from falling below thatrequired for proper slaking,bu t when the drums 2, 3, etc. are providedwith such steam jacket, assists .90 tities of water greatly in excess ofthose in removing from the slaked lime the excess water which itcontains, so that the final product will be a soft, dry, smooth,unstained, amorphous powder.

It will be understood, of course, that with the unslaked lime suppliedto the apparatus through the hopper 10 and an excess of water suppliedto the lime through the stack 11, the slaking operation takes place inthe drum 1 and is almost, if not completely, finished within said drum.The mass under treatment is stirred and fed along through the apparatusby means of the blades 9 on the shafts 8, the same passing from the drum1, through the hood 5 into the drum 2, thence through the hood 6 intothe drum. 3, and thence through the hood 7 into the drum 4, from whichit is finally discharged. The passage through the apparatus is slow. Theproper heat for the reaction between the Water and the unslaked lime ismaintained by the steam jacket around the drum 1, and all excessmoisture, due to the excess of water employedin the slaking operation,is removed by the current of air passing through the apparatus from thedischarge end, toward the stack, assisted by the heat from the steamjackets surrounding those portions of the apparatus below the drum 1.

I claim:

1, The process of hydrating lime which consists in feeding lime and insupplying Water to the lime in excess of the amount required forslaking, passing a current of air over the lime and supplying heat froman external source to the lime and water in the slaking zone in additionto that which is created by the reaction between the lime and water,whereby a proper slaking temperature may be maintained with an amount ofwater present in excess of that required to slake the lime.

2. The process of hydrating lime which consists in feeding lime to anelongated closed chamber and passing said lime through said chamber,supplyingthe lime at one end of the closed chamber with water in excessof the amount required for slaking, passing a current of air through.

said closed chamber and supplying. heat from an external source to thelime and water in the slaking zone in addition to that which is createdby the reaction between the lime and water, whereby a proper slakingtemperature may be maintained with an amount of water present in excessof that required to slake the lime.

3. The method of slaking lime in an elongated container, which consistsin continuously supplying unslaked lime to said container, continuouslysupplying water to the lime in quantities greatly in excess of theamount required for slaking, continuously stirring the mass undertreatment and feeding it through the container, and applying heat froman external source to the lime and Water in the slaking zone of saidcontainer in addition to that which is created by the reaction betweenthe lime and water to prevent thetemperature of the lime and water fromfallingbelow that required for proper slaking.

4. The method of slaking lime in an elongated container, which consistsin supplying unslaked lime to said container, supplying water to thelime in said container in quantities greatly in excess of the amountrequired for slaking, applying heat from an external source to the limeand water in the slaking zone of said container in addition to thatwhich is created by the reaction between the lime and water to preventthe tem perature of the lime and water from falling below that requiredfor proper slaking, stirring the mass under treatment and feeding itthrough the container, and applying additicnal heat to the slaked limewhile in the container after it passes from the slaking zone to removeexcess of moisture therefronm 5. The method of slaking lime in a seriesof containers, which consists in supplying unslaked lime in mass in thefirst of said series of containers, supplying water thereto greatly inexcess of the amount required for slaking said mass, applying heat froman external source to the lime and water in said first container inaddition to that which 'is created by the reaction between the lime andapplying additional heat to said treated.

mass while in one or more of said other containers to remove excessivemoisture from the slaked lime.

In witnem whereof, I subscribe my signature.

ALBERT ZIMMEBMAN.

